Sample project which dumbs down everything.

src/main/kotlin/lgbt/mystic/foundation/concrete/ConcreteExtension.kt

@@ -4,5 +4,6 @@ import org.gradle.api.provider.Property
 
 interface ConcreteExtension {
   val paperVersionGroup: Property<String>
+  val paperApiVersion: Property<String>
   val minecraftServerPath: Property<String>
 }

src/main/kotlin/lgbt/mystic/foundation/concrete/ConcreteProjectPlugin.kt

@@ -1,8 +1,20 @@
 package lgbt.mystic.foundation.concrete
 
+import com.github.jengelman.gradle.plugins.shadow.tasks.ShadowJar
+import org.gradle.api.JavaVersion
 import org.gradle.api.Plugin
 import org.gradle.api.Project
+import org.gradle.api.plugins.JavaPluginExtension
+import org.gradle.api.tasks.compile.JavaCompile
+import org.gradle.kotlin.dsl.get
+import org.gradle.kotlin.dsl.getByType
+import org.gradle.kotlin.dsl.repositories
+import org.gradle.kotlin.dsl.withType
+import org.gradle.language.jvm.tasks.ProcessResources
+import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
+import java.net.URI
 
+@Suppress("UnstableApiUsage")
 class ConcreteProjectPlugin : Plugin<Project> {
   override fun apply(project: Project) {
     val versionWithBuild = if (System.getenv("CI_PIPELINE_IID") != null) {
@@ -11,6 +23,52 @@ class ConcreteProjectPlugin : Plugin<Project> {
       "DEV"
     }
 
+    project.plugins.apply("org.jetbrains.kotlin.jvm")
+    project.plugins.apply("org.jetbrains.kotlin.plugin.serialization")
+    project.plugins.apply("com.github.johnrengelman.shadow")
+
     project.version = versionWithBuild
+
+    project.repositories {
+      maven {
+        name = "papermc"
+        url = URI.create("https://papermc.io/repo/repository/maven-public/")
+      }
+    }
+
+    val paperApiVersion = project.rootProject.extensions.getByType<ConcreteExtension>().paperApiVersion.get()
+
+    project.dependencies.add("compileOnly", "io.papermc.paper:paper-api:${paperApiVersion}")
+
+    project.extensions.getByType<JavaPluginExtension>().apply {
+      val javaVersion = JavaVersion.toVersion(17)
+      sourceCompatibility = javaVersion
+      targetCompatibility = javaVersion
+    }
+
+    (project.tasks.getByName("processResources") as ProcessResources).apply {
+      val props = mapOf("version" to project.version.toString())
+      inputs.properties(props)
+      filteringCharset = "UTF-8"
+      filesMatching("plugin.yml") {
+        expand(props)
+      }
+    }
+
+    (project.tasks["shadowJar"] as ShadowJar).apply {
+      archiveClassifier.set("plugin")
+    }
+
+    project.tasks["assemble"].dependsOn(project.tasks["shadowJar"])
+
+    project.tasks.withType<KotlinCompile>().forEach {
+      it.apply {
+        kotlinOptions.apply {
+          jvmTarget = "17"
+        }
+      }
+    }
+
+    project.rootProject.tasks["setupPaperServer"].dependsOn(project.tasks["shadowJar"])
   }
 }

src/main/kotlin/lgbt/mystic/foundation/concrete/ConcreteRootPlugin.kt

@@ -2,20 +2,14 @@ package lgbt.mystic.foundation.concrete
 
 import org.gradle.api.Plugin
 import org.gradle.api.Project
+import org.gradle.kotlin.dsl.apply
 import org.gradle.kotlin.dsl.create
 
-class ConcreteGradlePlugin : Plugin<Project> {
+class ConcreteRootPlugin : Plugin<Project> {
   override fun apply(project: Project) {
+    project.apply(plugin = "java")
     project.extensions.create<ConcreteExtension>("concrete")
     val setupPaperServer = project.tasks.create<SetupPaperServer>("setupPaperServer")
-    project.afterEvaluate { ->
-      setupPaperServer.dependsOn(*project.subprojects
-        // TODO: Foundation specific
-        .filter { it.isFoundationPlugin() }
-        .map { it.tasks.getByName("shadowJar") }
-        .toTypedArray()
-      )
-    }
     val runPaperServer = project.tasks.create<RunPaperServer>("runPaperServer")
     runPaperServer.dependsOn(setupPaperServer)
 

src/main/kotlin/lgbt/mystic/foundation/concrete/SetupPaperServer.kt

@@ -1,5 +1,6 @@
 package lgbt.mystic.foundation.concrete
 
+import com.github.jengelman.gradle.plugins.shadow.tasks.ShadowJar
 import org.gradle.api.DefaultTask
 import org.gradle.api.tasks.Input
 import org.gradle.api.tasks.TaskAction
@@ -39,17 +40,15 @@ open class SetupPaperServer : DefaultTask() {
       paperPluginsDirectory.mkdirs()
     }
 
-    for (project in project.subprojects) {
-      if (!project.isFoundationPlugin()) {
+    for (project in project.allprojects) {
+      if (!project.isPluginProject()) {
         continue
       }
 
-      val pluginJarFile = project.buildDir.resolve("libs/${project.name}-DEV-plugin.jar")
+      val task = project.tasks.getByName("shadowJar") as ShadowJar
+      val pluginJarFile = task.outputs.files.first()
       val pluginLinkFile = paperPluginsDirectory.resolve("${project.name}.jar")
-      if (pluginLinkFile.exists()) {
-        pluginLinkFile.delete()
-      }
-
+      pluginLinkFile.delete()
       Files.createSymbolicLink(pluginLinkFile.toPath(), pluginJarFile.toPath())
     }
   }

src/main/kotlin/lgbt/mystic/foundation/concrete/extensions.kt

@@ -5,9 +5,8 @@ import org.gradle.api.tasks.TaskOutputs
 import java.nio.file.FileSystems
 import java.nio.file.Path
 
-fun Project.isFoundationPlugin() = name.startsWith("foundation-")
-
-fun Project.findPluginProjects() = rootProject.subprojects.filter { project -> project.isFoundationPlugin() }
+fun Project.isPluginProject() = project.tasks.names.contains("shadowJar")
+fun Project.findPluginProjects() = rootProject.allprojects.filter { project -> project.isPluginProject() }
 
 val Project.shadowJarOutputs: TaskOutputs
   get() = project.tasks.getByName("shadowJar").outputs